CAJ | 학술논문

以化学气相渗透(CVI)技术制备的2D C/SiC复合材料为研究对象,探讨复合材料在700、1000和1300益空气环境中发生不同形式和不同程度氧化损伤后的阻尼行为变化。采用扫描电子显微镜( SEM)观察和分析复合材料的微结构损伤,采用动态力学分析仪(DMA)测试复合材料损伤前后的阻尼性能。结果表明：在700益和1000益空气环境中,随着氧化时间的延长,2D C/SiC复合材料的阻尼性能先增大后降低；而在1300益空气环境中,阻尼性能变化较小,且随氧化时间的延长未表现出明显的规律性。这是由于C/SiC复合材料的阻尼由炭纤维、热解炭界面和碳化硅基体,以及它们之间的相互作用共同形成。炭纤维和热解炭界面的氧化损伤会对复合材料阻尼特性产生两种影响机制,其一是使复合材料阻尼性能增大的机制,主要来自于热解炭界面相损耗引起的界面结合强度降低；其二是使复合材料阻尼性能降低的机制,主要来自于纤维的损耗和界面区的过度破坏。而碳化硅氧化生成的二氧化硅主要是通过影响碳相的氧化程度来影响复合材料的阻尼性能。
이화학기상삼투(CVI)기술제비적2D C/SiC복합재료위연구대상,탐토복합재료재700、1000화1300익공기배경중발생불동형식화불동정도양화손상후적조니행위변화。채용소묘전자현미경( SEM)관찰화분석복합재료적미결구손상,채용동태역학분석의(DMA)측시복합재료손상전후적조니성능。결과표명：재700익화1000익공기배경중,수착양화시간적연장,2D C/SiC복합재료적조니성능선증대후강저；이재1300익공기배경중,조니성능변화교소,차수양화시간적연장미표현출명현적규률성。저시유우C/SiC복합재료적조니유탄섬유、열해탄계면화탄화규기체,이급타문지간적상호작용공동형성。탄섬유화열해탄계면적양화손상회대복합재료조니특성산생량충영향궤제,기일시사복합재료조니성능증대적궤제,주요래자우열해탄계면상손모인기적계면결합강도강저；기이시사복합재료조니성능강저적궤제,주요래자우섬유적손모화계면구적과도파배。이탄화규양화생성적이양화규주요시통과영향탄상적양화정도래영향복합재료적조니성능。
A carbon fiber preform was chemical vapor infiltrated with a pyrocarbon ( PyC) interphase and a SiC matrix, and then coated with a SiC outer layer by chemical vapor deposition to prepare 2D C/SiC composites with a density of 2. 1 g/cm3 . The comˉ posites were oxidized at 700, 1000, 1300℃ for 2, 5 and 10h, respectively. The damping behavior of the oxidized composites was measured by a dynamical mechanical analyzer and the microstructural damage produced by the oxidation was investigated by scanˉ ning electron microscopy. Results show that the damping of the composites oxidized at 700℃ and 1 000℃ increases initially and then decreases with increasing oxidation time while that of the composites oxidized at 1 300℃ is independent of the oxidation time. The damping capacity of the C/SiC composites is determined by the carbon fibers, PyC interphase, SiC matrix and their interaction. The oxidation of the composites increases the damping by weakening the interfacial bonding due to the oxidation of PyC during the initial stage of oxidation, and decreases the damping by the oxidation loss of carbon fibers and excessive damage of the PyC interˉ phase during the latter stages of oxidation. SiO2 formed at 1 300℃ by the oxidation of SiC fills the voids produced by carbon oxidaˉ tion, which increases the dampingand compensates for the decrease of damping produced by carbon loss and excess damage of the PyC interphase.